抽水蓄能机组顶盖漏水原因分析

针对某抽水蓄能机组顶盖出现的漏水现象,对其在各个运行工况下的顶盖螺栓总载荷及残余预紧力进行了计算。由计算结果可以发现,由于在个别工况下残余预紧力小于0,导致了顶盖漏水,通过调整螺栓的伸长量,使得残余预紧力大于0,漏水现象得到了改善,但是预紧安全系数仍无法满足相关标准的要求。为此,进行了认真分析和复核。结果发现:在现有螺栓数量的基础上,通过增加预紧力虽然可以提高预紧的安全系数,但同时也得螺栓的总载荷增加,降低材料的安全系数,增加了螺栓断裂的可能性。针对新问题制定了相应的措施,即将螺栓小径由36 mm增加至52 mm后,通过增加预紧力提高预紧安全系数,保证螺栓连接的紧密性,村料的安全系数也得到了保证。改进后的螺栓在机组运行过程中服役安全。

Analysis on leakage at unit top cap of pumped storage generator

In the light of the top cap leakage of a pumped storage generator, the total load and residual pre-tightening force on the cap bolt under various working conditions was calculated and it was discovered that the leakage cause was the small residual pre-tightening force of less than 0. Through adjusting the bolt extension, the residual pre-tightening force became larger than 0 and the leakage was improved, but the pre-tightening coefficient still failed to meet the related demand. The serious analysis and re-examination showed that although the pre-tightening safety coefficient could be increased through increasing pre-tightening force for the original bolts, but in the meantime, the total load on the bolt increased, resulting in safety coefficient decease and the possibility increase of bolt broken. Aiming at these problems, the countermeasures were put forward, i.e, increasing the bolt diameter from 36 mm to 52 mm to increase the tightening force and the tightness of bolt connection as well as the ensuring the safety coefficients. The improved bolt serves safely in unit operation.